Bondo fiberglass resin jelly features a resin that is reinforced with milled fiberglass for a thicker consistency. More firm but still workable, it provides smooth, drip free application. It can be used in small holes and minor rust-outs without backing strips, cloths and mats. This waterproof fiberglass resin jelly is especially suitable for vertical surfaces on autos and boats. Bondo fiberglass resin jelly features tiny milled glass fibers that add strength and provide a thicker consistency for filling holes and rust-outs in auto body repair. This formula is ideal for vertical work such as car doors or boat hulls where standard resin can drip down the surface and cause extra work and cleanup. Also, there's no need for fiberglass mats, cloths and backing strips with small holes which cuts down on work time. For repairing larger holes where even more strength is needed, these added materials can be easily used. This fiberglass resin jelly filler is easily mixed using the included Bondo red cream hardener, designed specifically for use with Bondo fillers. It also features a fast drying formula that is sandable in as little as 20 min. This waterproof filler is ideal for repairing and filling minor rusted out holes in metal, wood and automotive fiberglass. It is compatible with all paint systems for cars and boats. As a brand of 3M, Bondo is well known among collision repair professionals and others who are committed to helping you restore the beauty and value to your cars and boats. This milled fiberglass reinforced resin jelly is another way that 3M applies science to life and helps you rediscover the excitement of the vehicles you own.